/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.madmatrix.zxing.android;

import java.io.IOException;
import java.text.DateFormat;
import java.util.Collection;
import java.util.Date;
import java.util.EnumSet;
import java.util.Map;

import org.madmatrix.zxing.android.camera.CameraManager;
import org.madmatrix.zxing.android.clipboard.ClipboardInterface;
import org.madmatrix.zxing.android.history.HistoryActivity;
import org.madmatrix.zxing.android.history.HistoryItem;
import org.madmatrix.zxing.android.history.HistoryManager;
import org.madmatrix.zxing.android.result.ResultButtonListener;
import org.madmatrix.zxing.android.result.ResultHandler;
import org.madmatrix.zxing.android.result.ResultHandlerFactory;
import org.madmatrix.zxing.android.result.supplement.SupplementalInfoRetriever;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.preference.PreferenceManager;
import android.util.Log;
import android.util.TypedValue;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.DecodeHintType;
import com.google.zxing.Result;
import com.google.zxing.ResultMetadataType;
import com.google.zxing.ResultPoint;

/**
 * This activity opens the camera and does the actual scanning on a background
 * thread. It draws a viewfinder to help the user place the barcode correctly,
 * shows feedback as the image processing is happening, and then overlays the
 * results when a scan is successful.
 * 
 * 此Activity所做的事：
 * 1. 开启camera，在后台独立线程中完成扫描任务；
 * 2. 绘制了一个扫描区（viewfinder）来帮助用户将条码置于其中以准确扫描；
 * 3. 扫描成功后会将扫描结果展示在界面上。
 * 
 * @author dswitkin@google.com (Daniel Switkin)
 * @author Sean Owen
 */
public final class CaptureActivity extends Activity implements SurfaceHolder.Callback {

    private static final String TAG = CaptureActivity.class.getSimpleName();

    private static final long DEFAULT_INTENT_RESULT_DURATION_MS = 1500L;

    private static final long BULK_MODE_SCAN_DELAY_MS = 1000L;

    public static final int HISTORY_REQUEST_CODE = 0x0000bacc;

    private static final Collection<ResultMetadataType> DISPLAYABLE_METADATA_TYPES = EnumSet.of(
            ResultMetadataType.ISSUE_NUMBER, 
            ResultMetadataType.SUGGESTED_PRICE,
            ResultMetadataType.ERROR_CORRECTION_LEVEL, 
            ResultMetadataType.POSSIBLE_COUNTRY);

    private CameraManager cameraManager;

    private CaptureActivityHandler handler;

    private Result savedResultToShow;

    private ViewfinderView viewfinderView;

    /**
     * 扫描提示，例如"请将条码置于取景框内扫描"之类的提示
     */
    private TextView statusView;

    /**
     * 扫描结果展示窗口
     */
    private View resultView;

    private Result lastResult;

    private boolean hasSurface;

    /**
     * 扫描后的结果是否自动复制到剪贴板
     */
    private boolean copyToClipboard;

    private IntentSource source;

    private ScanFromWebPageManager scanFromWebPageManager;

    /**
     * 【辅助解码的参数(用作MultiFormatReader的参数)】
     * 编码类型，该参数告诉扫描器采用何种编码方式解码，即EAN-13，QR Code等等
     * 对应于DecodeHintType.POSSIBLE_FORMATS类型
     * 参考DecodeThread构造函数中如下代码：hints.put(DecodeHintType.POSSIBLE_FORMATS, decodeFormats);
     */
    private Collection<BarcodeFormat> decodeFormats;

    /**
     * 【辅助解码的参数(用作MultiFormatReader的参数)】
     * 字符集，告诉扫描器该以何种字符集进行解码
     * 对应于DecodeHintType.CHARACTER_SET类型
     * 参考DecodeThread构造器如下代码：hints.put(DecodeHintType.CHARACTER_SET, characterSet);
     */
    private String characterSet;
    
    /**
     * 【辅助解码的参数(用作MultiFormatReader的参数)】
     * 该参数最终会传入MultiFormatReader，上面的decodeFormats和characterSet最终会先加入到decodeHints中
     * 最终被设置到MultiFormatReader中
     * 参考DecodeHandler构造器中如下代码：multiFormatReader.setHints(hints);
     */
    private Map<DecodeHintType, ?> decodeHints;

    /**
     * 扫描历史管理
     */
    private HistoryManager historyManager;

    /**
     * 活动监控器。如果手机没有连接电源线，那么当相机开启后如果一直处于不被使用状态则该服务会将当前activity关闭。
     * 活动监控器全程监控扫描活跃状态，与CaptureActivity生命周期相同.每一次扫描过后都会重置该监控，即重新倒计时。
     */
    private InactivityTimer inactivityTimer;

    /**
     * 声音震动管理器。如果扫描成功后可以播放一段音频，也可以震动提醒，可以通过配置来决定扫描成功后的行为。
     */
    private BeepManager beepManager;

    /**
     * 闪光灯调节器。自动检测环境光线强弱并决定是否开启闪光灯
     */
    private AmbientLightManager ambientLightManager;

    ViewfinderView getViewfinderView() {
        return viewfinderView;
    }

    public Handler getHandler() {
        return handler;
    }

    CameraManager getCameraManager() {
        return cameraManager;
    }

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        // 在扫描功能开启后，保持屏幕处于点亮状态
        Window window = getWindow();
        window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
        setContentView(R.layout.capture);

        // 这里仅仅是对各个组件进行简单的创建动作，真正的初始化动作放在onResume中
        hasSurface = false;
        historyManager = new HistoryManager(this);
        historyManager.trimHistory();
        inactivityTimer = new InactivityTimer(this);
        beepManager = new BeepManager(this);
        ambientLightManager = new AmbientLightManager(this);

        PreferenceManager.setDefaultValues(this, R.xml.preferences, false);
    }

    @Override
    protected void onResume() {
        super.onResume();

        // CameraManager must be initialized here, not in onCreate(). This is
        // necessary because we don't
        // want to open the camera driver and measure the screen size if we're
        // going to show the help on
        // first launch. That led to bugs where the scanning rectangle was the
        // wrong size and partially
        // off screen.
        /**
         * 上面这段话的意思是说，相机初始化的动作需要开启相机并测量屏幕大小，这些操作
         * 不建议放到onCreate中，因为如果在onCreate中加上首次启动展示帮助信息的代码的
         * 话，会导致扫描窗口的尺寸计算有误的bug
         */
        cameraManager = new CameraManager(getApplication());

        viewfinderView = (ViewfinderView) findViewById(R.id.viewfinder_view);
        viewfinderView.setCameraManager(cameraManager);
        resultView = findViewById(R.id.result_view);
        statusView = (TextView) findViewById(R.id.status_view);

        handler = null;
        lastResult = null;

        // 重置状态窗口，扫描窗口和结果窗口的状态
        resetStatusView();

        // 摄像头预览功能必须借助SurfaceView，因此也需要在一开始对其进行初始化
        // 如果需要了解SurfaceView的原理，参考:http://blog.csdn.net/luoshengyang/article/details/8661317
        SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);
        SurfaceHolder surfaceHolder = surfaceView.getHolder();
        if (hasSurface) {
            // The activity was paused but not stopped, so the surface still
            // exists. Therefore
            // surfaceCreated() won't be called, so init the camera here.
            initCamera(surfaceHolder);
        } else {
            // Install the callback and wait for surfaceCreated() to init the
            // camera.
            // 如果SurfaceView已经渲染完毕，会回调surfaceCreated，在surfaceCreated中调用initCamera()
            surfaceHolder.addCallback(this);
        }

        // 加载声音配置，其实在BeemManager的构造器中也会调用该方法，即在onCreate的时候会调用一次
        beepManager.updatePrefs();
        
        // 启动闪光灯调节器
        ambientLightManager.start(cameraManager);

        // 恢复活动监控器
        inactivityTimer.onResume();

        Intent intent = getIntent();

        // 加载配置，这些配置可以在应用启动后，在设置中进行设置，设置的结果会保存到SharePreferences中
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
        copyToClipboard = prefs.getBoolean(PreferencesActivity.KEY_COPY_TO_CLIPBOARD, true)
                && (intent == null || intent.getBooleanExtra(Intents.Scan.SAVE_HISTORY, true));

        source = IntentSource.NONE;
        decodeFormats = null;
        characterSet = null;

        // Barcode Scanner可以作为其他app的子组件来用，只需要通过Intent来调用即可
        // 如果需要设置一些参数来控制相机，可以将参数放在intent中
        if (intent != null) {
            String action = intent.getAction();

            // 调用方app通过设置Intent为com.google.zxing.client.android.SCAN来开启Barcode Scan的扫描功能
            // 这个设置动作在android-integation的IntenIntegrator中已设为默认的动作
            if (Intents.Scan.ACTION.equals(action)) {
                // Scan the formats the intent requested, and return the result
                // to the calling activity.
                source = IntentSource.NATIVE_APP_INTENT;
                decodeFormats = DecodeFormatManager.parseDecodeFormats(intent);
                decodeHints = DecodeHintManager.parseDecodeHints(intent);

                if (intent.hasExtra(Intents.Scan.WIDTH) && intent.hasExtra(Intents.Scan.HEIGHT)) {
                    int width = intent.getIntExtra(Intents.Scan.WIDTH, 0);
                    int height = intent.getIntExtra(Intents.Scan.HEIGHT, 0);
                    if (width > 0 && height > 0) {
                        cameraManager.setManualFramingRect(width, height);
                    }
                }

                String customPromptMessage = intent.getStringExtra(Intents.Scan.PROMPT_MESSAGE);
                if (customPromptMessage != null) {
                    statusView.setText(customPromptMessage);
                }
            }

            characterSet = intent.getStringExtra(Intents.Scan.CHARACTER_SET);
        }
    }

    @Override
    protected void onPause() {
        if (handler != null) {
            handler.quitSynchronously();
            handler = null;
        }
        
        // 暂停活动监控器
        inactivityTimer.onPause();
        
        // 停止闪光灯控制器
        ambientLightManager.stop();
        
        // 关闭摄像头
        cameraManager.closeDriver();
        if (!hasSurface) {
            SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);
            SurfaceHolder surfaceHolder = surfaceView.getHolder();
            surfaceHolder.removeCallback(this);
        }
        super.onPause();
    }

    @Override
    protected void onDestroy() {
        // 停止活动监控器
        inactivityTimer.shutdown();
        super.onDestroy();
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_BACK: // 拦截返回键
                if (source == IntentSource.NATIVE_APP_INTENT) {
                    setResult(RESULT_CANCELED);
                    finish();
                    return true;
                }
                if ((source == IntentSource.NONE)
                        && lastResult != null) {
                    restartPreviewAfterDelay(0L);
                    return true;
                }
                break;
            case KeyEvent.KEYCODE_FOCUS:
            case KeyEvent.KEYCODE_CAMERA:
                // Handle these events so they don't launch the Camera app
                return true;
                // Use volume up/down to turn on light
            case KeyEvent.KEYCODE_VOLUME_DOWN:
                cameraManager.setTorch(false);
                return true;
            case KeyEvent.KEYCODE_VOLUME_UP:
                cameraManager.setTorch(true);
                return true;
        }
        return super.onKeyDown(keyCode, event);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.menu.capture, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
        switch (item.getItemId()) {
            case R.id.menu_history:
                intent.setClassName(this, HistoryActivity.class.getName());
                startActivityForResult(intent, HISTORY_REQUEST_CODE);
                break;
            case R.id.menu_settings:
                intent.setClassName(this, PreferencesActivity.class.getName());
                startActivity(intent);
                break;
            case R.id.menu_help:
                intent.setClassName(this, HelpActivity.class.getName());
                startActivity(intent);
                break;
            default:
                return super.onOptionsItemSelected(item);
        }
        return true;
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent intent) {
        if (resultCode == RESULT_OK) {
            if (requestCode == HISTORY_REQUEST_CODE) {
                int itemNumber = intent.getIntExtra(Intents.History.ITEM_NUMBER, -1);
                if (itemNumber >= 0) {
                    HistoryItem historyItem = historyManager.buildHistoryItem(itemNumber);
                    decodeOrStoreSavedBitmap(null, historyItem.getResult());
                }
            }
        }
    }

    /**
     * 向CaptureActivityHandler中发送消息，并展示扫描到的图像
     * 
     * @param bitmap
     * @param result
     */
    private void decodeOrStoreSavedBitmap(Bitmap bitmap, Result result) {
        // Bitmap isn't used yet -- will be used soon
        if (handler == null) {
            savedResultToShow = result;
        } else {
            if (result != null) {
                savedResultToShow = result;
            }
            if (savedResultToShow != null) {
                Message message = Message.obtain(handler, R.id.decode_succeeded, savedResultToShow);
                handler.sendMessage(message);
            }
            savedResultToShow = null;
        }
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        if (holder == null) {
            Log.e(TAG, "*** WARNING *** surfaceCreated() gave us a null surface!");
        }
        if (!hasSurface) {
            hasSurface = true;
            initCamera(holder);
        }
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        hasSurface = false;
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    /**
     * A valid barcode has been found, so give an indication of success and show
     * the results.
     * 
     * @param rawResult The contents of the barcode.
     * @param scaleFactor amount by which thumbnail was scaled
     * @param barcode A greyscale bitmap of the camera data which was decoded.
     */
    public void handleDecode(Result rawResult, Bitmap barcode, float scaleFactor) {
        inactivityTimer.onActivity();
        lastResult = rawResult;
        ResultHandler resultHandler = ResultHandlerFactory.makeResultHandler(this, rawResult);

        boolean fromLiveScan = barcode != null;
        if (fromLiveScan) {
            historyManager.addHistoryItem(rawResult, resultHandler);
            // Then not from history, so beep/vibrate and we have an image to
            // draw on
            beepManager.playBeepSoundAndVibrate();
            drawResultPoints(barcode, scaleFactor, rawResult);
        }

        switch (source) {
            case NATIVE_APP_INTENT:
                handleDecodeExternally(rawResult, resultHandler, barcode);
                break;
            case NONE:
                SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
                // 如果在设置中选择了"批量扫描模式"，则扫描多个条码的时候，会对其逐一进行扫描，并将扫描到的结果保存在History中
                if (fromLiveScan && prefs.getBoolean(PreferencesActivity.KEY_BULK_MODE, false)) {
                    Toast.makeText(
                            getApplicationContext(),
                            getResources().getString(R.string.msg_bulk_mode_scanned) + " ("
                                    + rawResult.getText() + ')', Toast.LENGTH_SHORT).show();
                    // Wait a moment or else it will scan the same barcode
                    // continuously about 3 times
                    restartPreviewAfterDelay(BULK_MODE_SCAN_DELAY_MS);
                } else {
                    handleDecodeInternally(rawResult, resultHandler, barcode);
                }
                break;
        }
    }

    /**
     * Superimpose a line for 1D or dots for 2D to highlight the key features of
     * the barcode.
     * 
     * @param barcode A bitmap of the captured image.
     * @param scaleFactor amount by which thumbnail was scaled
     * @param rawResult The decoded results which contains the points to draw.
     */
    private void drawResultPoints(Bitmap barcode, float scaleFactor, Result rawResult) {
        ResultPoint[] points = rawResult.getResultPoints();
        if (points != null && points.length > 0) {
            Canvas canvas = new Canvas(barcode);
            Paint paint = new Paint();
            paint.setColor(getResources().getColor(R.color.result_points));
            if (points.length == 2) {
                paint.setStrokeWidth(4.0f);
                drawLine(canvas, paint, points[0], points[1], scaleFactor);
            } else if (points.length == 4
                    && (rawResult.getBarcodeFormat() == BarcodeFormat.UPC_A || rawResult
                            .getBarcodeFormat() == BarcodeFormat.EAN_13)) {
                // Hacky special case -- draw two lines, for the barcode and
                // metadata
                drawLine(canvas, paint, points[0], points[1], scaleFactor);
                drawLine(canvas, paint, points[2], points[3], scaleFactor);
            } else {
                paint.setStrokeWidth(10.0f);
                for (ResultPoint point : points) {
                    if (point != null) {
                        canvas.drawPoint(scaleFactor * point.getX(), scaleFactor * point.getY(),
                                paint);
                    }
                }
            }
        }
    }

    private static void drawLine(Canvas canvas, Paint paint, ResultPoint a, ResultPoint b,
            float scaleFactor) {
        if (a != null && b != null) {
            canvas.drawLine(scaleFactor * a.getX(), scaleFactor * a.getY(), scaleFactor * b.getX(),
                    scaleFactor * b.getY(), paint);
        }
    }

    // Put up our own UI for how to handle the decoded contents.
    /**
     * 该方法会将最终处理的结果展示到result_view上。并且如果选择了"检索更多信息"则会内部对结果进行进一步的查询
     * 
     * @param rawResult
     * @param resultHandler
     * @param barcode
     */
    private void handleDecodeInternally(Result rawResult, ResultHandler resultHandler,
            Bitmap barcode) {
        statusView.setVisibility(View.GONE);
        viewfinderView.setVisibility(View.GONE);
        resultView.setVisibility(View.VISIBLE);

        ImageView barcodeImageView = (ImageView) findViewById(R.id.barcode_image_view);
        if (barcode == null) {
            barcodeImageView.setImageBitmap(BitmapFactory.decodeResource(getResources(),
                    R.drawable.launcher_icon));
        } else {
            barcodeImageView.setImageBitmap(barcode);
        }

        TextView formatTextView = (TextView) findViewById(R.id.format_text_view);
        formatTextView.setText(rawResult.getBarcodeFormat().toString());

        TextView typeTextView = (TextView) findViewById(R.id.type_text_view);
        typeTextView.setText(resultHandler.getType().toString());

        DateFormat formatter = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT);
        TextView timeTextView = (TextView) findViewById(R.id.time_text_view);
        timeTextView.setText(formatter.format(new Date(rawResult.getTimestamp())));

        TextView metaTextView = (TextView) findViewById(R.id.meta_text_view);
        View metaTextViewLabel = findViewById(R.id.meta_text_view_label);
        metaTextView.setVisibility(View.GONE);
        metaTextViewLabel.setVisibility(View.GONE);
        Map<ResultMetadataType, Object> metadata = rawResult.getResultMetadata();
        if (metadata != null) {
            StringBuilder metadataText = new StringBuilder(20);
            for (Map.Entry<ResultMetadataType, Object> entry : metadata.entrySet()) {
                if (DISPLAYABLE_METADATA_TYPES.contains(entry.getKey())) {
                    metadataText.append(entry.getValue()).append('\n');
                }
            }
            if (metadataText.length() > 0) {
                metadataText.setLength(metadataText.length() - 1);
                metaTextView.setText(metadataText);
                metaTextView.setVisibility(View.VISIBLE);
                metaTextViewLabel.setVisibility(View.VISIBLE);
            }
        }

        TextView contentsTextView = (TextView) findViewById(R.id.contents_text_view);
        CharSequence displayContents = resultHandler.getDisplayContents();
        contentsTextView.setText(displayContents);
        // Crudely scale betweeen 22 and 32 -- bigger font for shorter text
        int scaledSize = Math.max(22, 32 - displayContents.length() / 4);
        contentsTextView.setTextSize(TypedValue.COMPLEX_UNIT_SP, scaledSize);

        TextView supplementTextView = (TextView) findViewById(R.id.contents_supplement_text_view);
        supplementTextView.setText("");
        supplementTextView.setOnClickListener(null);
        /**
         * 更进一步对扫描结果进行检索
         * 如果在设置中选择了“检索更多信息”则会在扫描出isbn号之后自动去网上查询该书的信息，
         * 最后将书的信息展示出来，而如果没选中，则只会将isbn号码展示。
         */
        if (PreferenceManager.getDefaultSharedPreferences(this).getBoolean(
                PreferencesActivity.KEY_SUPPLEMENTAL, true)) {
            SupplementalInfoRetriever.maybeInvokeRetrieval(supplementTextView,
                    resultHandler.getResult(), historyManager, this);
        }

        int buttonCount = resultHandler.getButtonCount();
        ViewGroup buttonView = (ViewGroup) findViewById(R.id.result_button_view);
        buttonView.requestFocus();
        for (int x = 0; x < ResultHandler.MAX_BUTTON_COUNT; x++) {
            TextView button = (TextView) buttonView.getChildAt(x);
            if (x < buttonCount) {
                button.setVisibility(View.VISIBLE);
                button.setText(resultHandler.getButtonText(x));
                button.setOnClickListener(new ResultButtonListener(resultHandler, x));
            } else {
                button.setVisibility(View.GONE);
            }
        }

        if (copyToClipboard && !resultHandler.areContentsSecure()) {
            ClipboardInterface.setText(displayContents, this);
        }
    }

    // Briefly show the contents of the barcode, then handle the result outside
    // Barcode Scanner.
    /**
     * 同handleDecodeInternally的区别是，handleDecodeInternally是对扫描结果自行查询处理
     * handleDecodeExternally则是将扫描的结果拼凑到用户指定的url中并用浏览器进行访问
     * 具体规则可参考：ScanFromWebPageManager类
     * 
     * @param rawResult
     * @param resultHandler
     * @param barcode
     */
    private void handleDecodeExternally(Result rawResult, ResultHandler resultHandler,
            Bitmap barcode) {

        if (barcode != null) {
            viewfinderView.drawResultBitmap(barcode);
        }

        long resultDurationMS;
        if (getIntent() == null) {
            resultDurationMS = DEFAULT_INTENT_RESULT_DURATION_MS;
        } else {
            resultDurationMS = getIntent().getLongExtra(Intents.Scan.RESULT_DISPLAY_DURATION_MS,
                    DEFAULT_INTENT_RESULT_DURATION_MS);
        }

        if (resultDurationMS > 0) {
            String rawResultString = String.valueOf(rawResult);
            if (rawResultString.length() > 32) {
                rawResultString = rawResultString.substring(0, 32) + " ...";
            }
            statusView.setText(getString(resultHandler.getDisplayTitle()) + " : " + rawResultString);
        }

        if (copyToClipboard && !resultHandler.areContentsSecure()) {
            CharSequence text = resultHandler.getDisplayContents();
            ClipboardInterface.setText(text, this);
        }

        // Hand back whatever action they requested - this can be changed to
        // Intents.Scan.ACTION when
        // the deprecated intent is retired.
        Intent intent = new Intent(getIntent().getAction());
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
        intent.putExtra(Intents.Scan.RESULT, rawResult.toString());
        intent.putExtra(Intents.Scan.RESULT_FORMAT, rawResult.getBarcodeFormat().toString());
        byte[] rawBytes = rawResult.getRawBytes();
        if (rawBytes != null && rawBytes.length > 0) {
            intent.putExtra(Intents.Scan.RESULT_BYTES, rawBytes);
        }
        Map<ResultMetadataType, ?> metadata = rawResult.getResultMetadata();
        if (metadata != null) {
            if (metadata.containsKey(ResultMetadataType.UPC_EAN_EXTENSION)) {
                intent.putExtra(Intents.Scan.RESULT_UPC_EAN_EXTENSION,
                        metadata.get(ResultMetadataType.UPC_EAN_EXTENSION).toString());
            }
            Number orientation = (Number) metadata.get(ResultMetadataType.ORIENTATION);
            if (orientation != null) {
                intent.putExtra(Intents.Scan.RESULT_ORIENTATION, orientation.intValue());
            }
            String ecLevel = (String) metadata.get(ResultMetadataType.ERROR_CORRECTION_LEVEL);
            if (ecLevel != null) {
                intent.putExtra(Intents.Scan.RESULT_ERROR_CORRECTION_LEVEL, ecLevel);
            }
            @SuppressWarnings("unchecked")
            Iterable<byte[]> byteSegments = (Iterable<byte[]>) metadata
                    .get(ResultMetadataType.BYTE_SEGMENTS);
            if (byteSegments != null) {
                int i = 0;
                for (byte[] byteSegment : byteSegments) {
                    intent.putExtra(Intents.Scan.RESULT_BYTE_SEGMENTS_PREFIX + i, byteSegment);
                    i++;
                }
            }
        }
        sendReplyMessage(R.id.return_scan_result, intent, resultDurationMS);
    }

    private void sendReplyMessage(int id, Object arg, long delayMS) {
        if (handler != null) {
            Message message = Message.obtain(handler, id, arg);
            if (delayMS > 0L) {
                handler.sendMessageDelayed(message, delayMS);
            } else {
                handler.sendMessage(message);
            }
        }
    }

    private void initCamera(SurfaceHolder surfaceHolder) {
        if (surfaceHolder == null) {
            throw new IllegalStateException("No SurfaceHolder provided");
        }
        if (cameraManager.isOpen()) {
            Log.w(TAG, "initCamera() while already open -- late SurfaceView callback?");
            return;
        }
        try {
            cameraManager.openDriver(surfaceHolder);
            // Creating the handler starts the preview, which can also throw a
            // RuntimeException.
            if (handler == null) {
                handler = new CaptureActivityHandler(this, decodeFormats, decodeHints,
                        characterSet, cameraManager);
            }
            decodeOrStoreSavedBitmap(null, null);
        } catch (IOException ioe) {
            Log.w(TAG, ioe);
            displayFrameworkBugMessageAndExit();
        } catch (RuntimeException e) {
            // Barcode Scanner has seen crashes in the wild of this variety:
            // java.?lang.?RuntimeException: Fail to connect to camera service
            Log.w(TAG, "Unexpected error initializing camera", e);
            displayFrameworkBugMessageAndExit();
        }
    }

    private void displayFrameworkBugMessageAndExit() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle(getString(R.string.app_name));
        builder.setMessage(getString(R.string.msg_camera_framework_bug));
        builder.setPositiveButton(R.string.button_ok, new FinishListener(this));
        builder.setOnCancelListener(new FinishListener(this));
        builder.show();
    }

    /**
     * 在经过一段延迟后重置相机以进行下一次扫描。
     * 成功扫描过后可调用此方法立刻准备进行下次扫描
     * 
     * @param delayMS
     */
    public void restartPreviewAfterDelay(long delayMS) {
        if (handler != null) {
            handler.sendEmptyMessageDelayed(R.id.restart_preview, delayMS);
        }
        resetStatusView();
    }

    /**
     * 展示状态视图和扫描窗口，隐藏结果视图
     */
    private void resetStatusView() {
        resultView.setVisibility(View.GONE);
        statusView.setText(R.string.msg_default_status);
        statusView.setVisibility(View.VISIBLE);
        viewfinderView.setVisibility(View.VISIBLE);
        lastResult = null;
    }

    public void drawViewfinder() {
        viewfinderView.drawViewfinder();
    }
}
